Mesenchymal stem cells (MSCs) are adult stem cells that were initially isolated from bone marrow. However, subsequent research has shown that other adult tissues also contain MSCs. MSCs originate from mesenchyme, which is embryonic tissue derived from the mesoderm. These cells actively proliferate, giving rise to new cells in some tissues, but remain quiescent in others. MSCs are capable of differentiating into multiple cell types including adipocytes, chondrocytes, osteocytes, and cardiomyocytes. Isolation and induction of these cells could provide a new therapeutic tool for replacing damaged or lost adult tissues. However, the biological properties and use of stem cells in a clinical setting must be well established before significant clinical benefits are obtained. This paper summarizes data on the biological properties of MSCs and discusses current and potential clinical applications.

Because of their ease of isolation and relative abundance, adipose-derived mesenchymal stem cells (ASCs) are a particularly attractive autologous cell source for various therapeutic purposes. ASCs retain a high proliferation capacity in vitro and have the ability to undergo extensive differentiation into multiple cell lineages. Moreover, ASCs secrete a wide range of growth factors that can stimulate tissue regeneration. Therefore, the clinical use of ASCs is feasible. However, the potential of ASCs differs depending on the donor’s medical condition, including diseases such as diabetes. Recent studies demonstrated that ASCs from diabetic donors exhibit reduced proliferative potential and a smaller proportion of stem cell marker-positive cells. Therefore, to ensure the success of regenerative medicine, tissue engineering methods must be improved by the incorporation of factors that increase the proliferation and differentiation of stem/progenitor cells when autologous cells are used. Platelet-rich plasma (PRP), which contains high levels of diverse growth factors that can stimulate stem cell proliferation and cell differentiation in the context of tissue regeneration, has recently been identified as a biological material that could be applied to tissue regeneration. Thus, co-transplantation of ASCs and PRP represents a promising novel approach for cell therapy in regenerative medicine. In this review, we describe the potential benefits of adding PRP to ASCs and preclinical and clinical studies of this approach in various medical fields. We also discuss the mechanisms of PRP action and future cell-based therapies using co-transplantation of ASCs and PRP.

Background: Tendinopathy is a common and highly prevalent musculoskeletal disorder characterized by repetitive activity-related pain and focal tendon tenderness. Histopathologically, tendinopathic tissue mainly shows degenerative changes. Therefore, tendinopathy is not affected by anti-inflammatory therapies. A novel approach, including a stem cell–based therapy, may be beneficial for its treatment. Purpose/Hypothesis: The purpose of this study was to evaluate the effects of adipose-derived stem cells (ASCs) on tendon healing in a rat tendinopathy model. The hypothesis was that ASC transplantation would improve degeneration in collagenase-induced tendinopathy. Study Design: Controlled laboratory study. Methods: Sixteen F344/NSlc rats underwent collagenase injection into the Achilles tendon to induce tendinopathy. At 1 week after collagenase injection, 8 rats received ASCs (ASC group) and 8 received phosphate-buffered saline alone (PBS group). Animals were sacrificed at 4 or 12 weeks after ASC administration, and the degree of degeneration in each tendon was histologically evaluated according to the Bonar scale. The microstructure of healing tendons was observed by scanning electron microscopy. Reverse-transcription polymerase chain reaction (RT-PCR) was performed to measure the ratio of type III collagen messenger RNA (mRNA) to type I collagen mRNA in tendons. Results: The median Bonar scale score in the ASC and PBS groups was 2.5 and 5.33 at 4 weeks after treatment and 1.0 and 4.0 at 12 weeks after treatment, respectively. Histologically, the ASC group showed a significantly lower degree of tendon degeneration than the PBS group at both time points. In the RT-PCR analysis, the ratio of type III collagen to type I collagen was significantly lower in the ASC group than in the PBS group at 12 weeks after treatment. Moreover, this ratio decreased over time in the ASC group, whereas it increased over time in the PBS group. Conclusion: The study findings demonstrate that the application of ASCs results in significant improvement in the pathological findings associated with tendinopathy and the normalization of collagen ratios within the affected tendon. Clinical Relevance: Subcutaneous adipose tissue can be harvested easily, and ASC administration might have the potential to rapidly treat tendinopathy.

Background: Basic fibroblast growth factors (bFGFs) play a crucial role in wound healing by promoting fibroblast proliferation and neovascularization. However, drawback of bFGF is short half-life in free form. Gelatin has a capability of sustaining growth factors, which are gradually released while degradation. The purpose of this study is to see whether bFGF-impregnated gelatin sheet is effective in a murine model and whether it could also be available for patients in a safe manner. Methods: Full-thickness skin defect was created on C57BL/6J mice and covered with bFGF with gelatin sheet (group A), bFGF without gelatin sheet (group B), phosphate buffer saline (PBS) with gelatin sheet (group C), and only PBS (group D). Wound healing was evaluated in terms of percent wound closure, granulation thickness, wound maturity, and vascular density. Clinical trial was conducted for patients who received either acute or chronic ulcers. The sheets were put onto the wounds and covered by hydrocolloid dressing, which was changed weekly. Results: Groups A and B exhibited better wound healing than groups C and D in all aspects. Moreover, group A showed better results than group B at day 7 in terms of wound closure, collagen maturity, and vascularity. Efficacy without any adverse events was found in the clinical series. Conclusions: These findings suggest that control-released bFGF using gelatin sheet is effective for promoting wound healing. Such therapeutic strategy was considered to offer several clinical advantages including rapid healing and reduction of the dressing change with less patient discomfort.